1. Field of the Invention
The invention relates to communications, and in particular, to determining communication signaling parameters.
2. Description of the Prior Art
Signaling protocols enable destination networks to pass parameters for inducing events on source networks. Typically, the parameters in reply signaling induce an event at the caller's device to alert the caller of the status of the call, such as a ring-back tone, slow busy signal, or a fast busy signal. In the prior art, the destination network determined a parameter for reply signaling based on the status of a call. For example, user A on a source network places a call to user B on a destination network. The destination network determines that user B is available and sends a parameter within reply signaling back to the source network to induce a ring-back sound on user A's device.
Often times, the signaling protocols of the source and destination networks differ and signaling gateways are employed to translate signaling at an interface between the two networks. Parameters sent from the destination network are translated at the gateway according to instructions from the source network operator, regardless of the signaling protocol of the source network. Typically, the destination network could rely upon a stable translation between the destination and source protocols.
Recently, voice over internet protocol (VOIP) telephony has become a popular service. Many variations of signaling have been developed to support VOIP because VOIP signaling can be easily customized and modified to provide enhanced service to VOIP users. Due to the ease with which network operators can modify source protocols, other networks can no longer assume that the same parameter selection by the destination network will induce the same event in every source network. As a result, when destination networks send event-inducing parameters to source networks, source networks oftentimes initiate or direct events that are not desired by the destination networks.
What is needed is a system that allows a destination network to predictably induce events on devices communicating across communication networks regardless of the source signaling protocol.